The transducer can by way of example convert mechanical signals that are generated by virtue of the diaphragm deflecting into electrical signals. The electrical signals can be generated by way of example by virtue of a change in a capacitance between the diaphragm and a non-moveable backplate, wherein a voltage is applied between the diaphragm and the backplate. The mechanical signals that deflect the diaphragm can be generated by way of example by means of sound waves or other fluctuations in pressure. Accordingly, the transducer can be used as a microphone and measure the sound waves. The transducer can also be used as a pressure sensor.
A method for producing such a microelectromechanical transducer is known from EP 1 093 703 B1. In the case of the method that is described in EP 1 093 703 B1, the tension of all the diaphragms is adjusted retrospectively in a common method step for a batch that comprises a plurality of wafers, wherein each wafer comprises in turn a transducer having a diaphragm.
However, in the case of this method, each diaphragm of the batch is always treated in an identical manner. It is accordingly not possible to compensate for differences between the individual diaphragms of a wafer, said differences can occur during the production process. Consequently, when the predetermined limits for the tensions of the diaphragms that are to be produced are very narrow, the method results in a significant part of the diaphragms remaining outside these limits and leads to the fact that it is moreover not possible to retrospectively adjust these diaphragms individually to a satisfactory extent. Accordingly, the number of rejects is significant.
A Gaussian-curve-like distribution of the tensions of the diaphragms typically occurs during the production of a wafer. The method in accordance with EP 1 093 703 B1 renders it possible to displace the mean value of this distribution. However, it does not render it possible to change the shape of the distribution. When the predetermined specification limits are narrow, a significant part of the transducer produced will comprise a diaphragm whose tension lies outside the predetermined specification limits even after the method has been implemented.